7g (0.25oz)sugar(optional if you prefer a more tart lemon surprise)
2.5g (one sheet)agar-agar
French Hollow Meringues:
Using an electric whisk or a stand-mixer, beat the egg whites at medium speed until the whites start to foam. Add 1/3 of the sugar then increase speed until the meringue starts to form. Gradually add the rest of the sugar while beating until the peaks are soft, shiny yet firm.
Stop the mixer and fold in the icing sugar using a spatula until well incorporated. Transfer the meringue to a piping bag with a plain 10mm tip then pipe out spiral mounds around an upturned silicone mini cake mould.
Bake in a cool oven at 80°C fan for 2 hours (according to the chef but I can't make my oven that low - so baked at 110°C fan/130°C/250°F/gas 1/2 for 2 hours. As the meringues were bigger than his minis, it still worked out well at 2 hours. After 2 hours, switch off the oven, open the door and leave inside for 10 minutes. Remove to cool then lift off the moulds.
Once cool, grate the wispy tops off half of the meringue shells to smooth in order to let the meringues stand upright.
In a small saucepan, bring the lemon juice and water to the boil. Add the sugar (if using) and the agar-agar.
Pour the mixture immediately into mini silicone cake moulds (preferably the same size as the meringues) and leave to set in the fridge for at least 30 minutes. Once set, they're easy to remove from the moulds.
Toast the hazelnuts under a hot grill for a couple of minutes. When cooler and able to handle, rub the hazelnuts between your hands to easily take off the skins.
Gradually heat half of the sugar with a few drops of water in a small saucepan until it starts to melt. Add the rest of the sugar and leave to melt until a golden caramel forms.
Immediately transfer the warm, liquid caramel to a food processor and mix together with the toasted hazelnuts until it forms a soft paste. Transfer to a piping bag.
Using an electric whisk or a stand-mixer, whisk the whipping cream with the vanilla on high until it thickens. Whisk in the mascarpone then transfer to a piping bag.
Separate the meringue shells into couples for each Melting Meringue. Pipe in the praline into one half, top with the lemon jelly. In the other halves, pipe in the vanilla cream and add half a candied chestnut.
Stick both halves of each meringue together with the cream. Add a tiny blob of cream on top and garnish with white chocolate and gold leaf.
Decorate with gold leaf and white chocolate shavings. Sprinkle each meringue with the meringue powder, following grating of each base.